The invention relates to a structure or arrangement for connecting two pipes, and in particular, for connecting a fuel filler pipe to a fuel tank pipe of a motor vehicle.
Well-known and widely used pipe connections include arrangements wherein one pipe has an external thread in the connection area that a screw cap or nut located on a second pipe screws onto.
A motor vehicle usually includes a fuel tank and a conduit for introducing liquid fuel into the fuel tank, commonly referred to as a fuel filler pipe. The connection between the filler pipe and the fuel tank usually involves two pipes, one end of the filler pipe and another pipe that is welded or otherwise secured to the fuel tank. It is a well-known practice to slide a flexible filler hose or sleeve over the two adjoining pipe ends and introduce a surrounding hose clamp in order to connect the two pipes. This flexible sleeve is commonly made of rubber or other material with suitable heat resistance and weatherability. However, rubber is permeable to hydrocarbon fumes, so the rubber sleeve absorbs fuel over time, leading to unpleasant odors, and more importantly, the release of toxic hydrocarbon fumes into the surrounding atmosphere. Furthermore, a need also exists in other applications for a tight connection of two pipes that is impermeable to both gases and liquids.
Therefore, an object of the invention is to provide an arrangement for a connection of two pipes that is impermeable to fluids and, as much as possible, to gases such as hydrocarbon fumes.
Other objects and advantages of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing.
The invention provides a ring seal, which can be clamped in between a flexible ring-shaped collar of one pipe and an inner cone of a second pipe by means of a screw connection. Any potential permeation of vapors or gases, in particular hydrocarbon vapors emanating from the fuel, is limited to the very small surface area of the ring seal which is in contact with the external environment.
The flexible ring-shaped collar increases the impermeability of the entire arrangement. This flexibility can be achieved by designing the ring-shaped collar with two flanks that are resilient against each other.
To achieve a perfect fit and protect against slipping, the front transitional area between the ring-shaped collar and the pipe provides a bearing surface for an O-ring seal.
The screw connection includes a connecting nut that is held by the ring-shaped collar of one pipe and a threaded part that is located on the other pipe.
In one possible embodiment, the threaded part is a plastic part that is injection-molded directly onto the pipe. In another embodiment, the threaded part is a metal part that is pressed onto the pipe. Both embodiments allow the threaded part to be easily produced and attached.
To ensure a tight screw connection, the threaded part must be attached tightly. For this purpose, the threaded part is held in an interlocking manner at the pipe, in particular by means of ribs or other similar means, at the circumference of the pipe.